Add a metric to Chrome to measure fragmentation of chrome.dll at startup.BUG=98033TEST=None

chrome/browser/fragmentation_checker_win.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_FRAGMENTATION_CHECKER_WIN_H_
+#define CHROME_BROWSER_FRAGMENTATION_CHECKER_WIN_H_
+#pragma once
+
+class FilePath;
+
+namespace fragmentation_checker {
+
+const int kMaxExtentCount = 1 << 16;
+
+// Returns the number of extents for the file at |file_path|. The number is
+// capped at kMaxExtentCount, files with more extents than that will be counted
+// as having kMaxExtentCount extents. On failure, this function returns 0.
+int CountFileExtents(const FilePath& file_path);
+
+// Records fragmentation metrics for the current module. This records the number
+// of fragments the current module is stored in.
+// This will be used to determine whether pursuing more aggressive
+// manual defragmentation is worth the effort.
+void RecordFragmentationMetricForCurrentModule();
+
+}  // namespace fragmentation_checker
+
+#endif  // CHROME_BROWSER_FRAGMENTATION_CHECKER_WIN_H_